3M Hard Hat Ear muffs for hard hats (sold separately) feature lighweight ear cups that attach to a variety of hard hats without additional adapters. The multiposition ear cups are beveled to fit comfortably under the hard hat. Ear cups flip up and lock in place when not in use. Contoured ear cushion for improved fit and comfort. Soft sealing cushions and molded foam ear cup inserts are easily replaceable. Noise Reduction Rating: 23 dB.